An approach computer device is provided for an aircraft approaching a landing field to enable the pilot to have before him during the approach a device which shows the distance to the landing field and, correlated with that distance, the altitude at which the plane should be flying at such distance. The distance to be flown is set as the plane passes over the final approach fix from which the plane is to approach the field at a constant rate of speed. The device is calibrated to provide a consta...

An electronic clock making use of an electromagnetically actuated tuning fork whose vibrations are converted into rotary motion for driving the gear train of the clock by means of a motion transformer including a V-shaped indexing element. The ends of the indexing element are attached to the tines of the fork at corresponding points thereon, and the vertex thereof is flattened to define a rectangular tongue whose edge engages the ratchet teeth of an index wheel whereby as the tines vibrate, the ...

A timekeeping device is provided with a mechanical oscillator electronically sustained without contact. A balance-wheel bearing permanent magnets induces electromotive force in two coils placed at the point of static equilibrium of the wheel. The electromotive forces are used in an amplifier transistor to supply through a third coil coaxial with the two previous ones a sustaining power, and are further used to control a regulator transistor which acts upon the point of operation of the amplifier...

A time correction device for electronic watches having multi-stage divider circuitry for dividing the high frequency output signals of an oscillator into low frequency timing signals including a gate at the input of each divider stage to be corrected for selectively applying to said divider stage the output signal of the prior stage or the inverse of said prior stage output signal. A switch is provided for manually actuating the gate to pass one of the prior stage output signal and the inverse t...

An electronic wristwatch in which time is displayed by means of a plurality of separately sealed, independently rotatable, coplanar concentric rings. Each ring carries a plurality of magnetic domains and is independently stepped by a set of electromagnets driven by a multiphase pulse train. Typically, each ring is stepped at a different rate so as to display a different unit of time, this being achieved by suitably scaling the frequencies of the multiphase pulse trains which drive the different ...

An electric clock mounting and contact apparatus including an electric clock housing, an electric drive circuit positioned within the housing, pillar means extending between the housing and the electric drive circuit for supporting said electric drive circuit, the pillar means being electrically conductive and in electrical contact with the electric drive circuit, an electrical contact means connected exteriorly of the electrical clock housing and to the pillar means, said electrical contact mea...

An electrical cell is secured in a trough shaped housing in a plate of a timepiece movement by a device located at the periphery of the housing. Said device comprises at least one member such as a washer with a cut-away edge held by means of a screw which moves it, from a rest position in which the cell is free, downwardly and inwardly into the housing to an operative position biting into the wall of the cell which is firmly held against a contact in the housing.

A wrist watch has a glass fitted in a snap. An inwardly facing groove in the snap, normally closed by the glass, houses a miniature bulb connected by wires passing through watertightly-closed openings communicating the snap with the outside of the watch case. The wires are connected to batteries housed in extensions to the watch case, said extensions including a switch to enable illumination of the bulb by a pressure on the wearer's wrist.

An automatic time indicator for use during a chess match. A control circuit is provided to alternately control the running of respective players' time clocks without any direct manual intervention, relying on circuitry in the chess board itself and the placement of a chess piece on a new square by any player.

An apparatus for driving an electric watch having a balance wheel which is driven electro-magnetically, wherein driving current is alternately applied in opposite directions to the driving coil.